Fabric Items Having Strands With Inner and Outer Layers

ABSTRACT

A fabric-based item may include fabric formed from intertwined strands of material. The strands of material may include interior layers and exterior layers that surround the interior layers. The interior layers may have different properties from the exterior layers, such as different conductivities, adhesiveness, magnetic properties, colors, reflectivities, as examples. The strands of material may be selectively etched to expose portions of the interior layers. In this way, the properties of the interior layers may be visible and/or exposed, and the strands may have a modified appearance or functionality in the exposed regions. Other strands or external equipment may be coupled to the interior layers within the exposed regions. Adjacent strands in a layer of fabric may have adjoining exposed portions to modify the properties of a region of the layer of fabric.

This application claims the benefit of provisional patent application No. 63/348,407, filed Jun. 2, 2022, which is hereby incorporated by reference herein in its entirety.

FIELD

This relates generally to fabric-based items and, more particularly, to fabric-based items formed from strands of material.

BACKGROUND

It may be desirable to form bags, furniture, clothing, wearable electronic devices, and other items from materials such as fabric. If care is not taken, however, fabric-based items may not offer desired features. For example, fabric-based items may include fabric that is completely uniform. The use of uniform fabric may make it difficult to satisfy design and functionality goals when forming a fabric-based item.

SUMMARY

A fabric-based item may include fabric formed from intertwined strands of material. The strands of material may include interior and external layers, such as an interior yarn and an exterior yarn. The external layer may surround the internal layer.

The layer of fabric may have first and second portions. Strands in the first portions of the layer of fabric may have some of the exterior yarn removed to expose the interior yarn. Strands in the second portion may have the exterior yarn fully surrounding the interior yarn.

The interior yarn and exterior yarn may have different properties. For example, the interior yarn and exterior yarn may have different colors, reflectivities, magnetic properties, conductivities, adhesiveness, and/or other desired properties. By selectively exposing the interior yarn in the first portions of the layer of fabric, the first portions may have different properties than the second portions.

Other strands, such as conductive strands, or other equipment may be coupled to the exposed portions of the interior yarn. Adjacent strands in a layer of fabric may have adjoining exposed portions to modify the properties of a region of the layer of fabric.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an illustrative fabric-based item in accordance with an embodiment.

FIG. 2 is a side view of illustrative woven fabric in accordance with an embodiment.

FIG. 3 is a top view of illustrative knit fabric in accordance with an embodiment.

FIG. 4 is a diagram of illustrative equipment for forming a fabric-based item in accordance with an embodiment.

FIG. 5 is a diagram of an illustrative strand with a core and an exterior layer surrounding the core in accordance with an embodiment.

FIG. 6A is a diagram of an illustrative strand having an etched portion in accordance with an embodiment.

FIG. 6B is a diagram of an illustrative strand having an etched portion of an exterior layer to reveal a core in accordance with an embodiment.

FIG. 7 is a diagram of an illustrative strand have a core, an additional layer, and an exterior layer surrounding the core and the additional layer in accordance with an embodiment.

FIG. 8 is a diagram of an illustrative fabric that includes etched strands to form portions of the fabric with different appearances in accordance with an embodiment.

DETAILED DESCRIPTION

Items such as item 10 of FIG. 1 may be based on fabric. Item 10 may be an electronic device or an accessory for an electronic device. For example, item 10 may be a portion of a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user's head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a remote control, a navigation device, an embedded system such as a system in which fabric-based item 10 is mounted in a kiosk, in an automobile, airplane, or other vehicle, other electronic equipment, or may be equipment that implements the functionality of two or more of these devices, or may be an accessory for one or more of the forgoing devices. If desired, item 10 may be a removable external case for electronic equipment, may be a strap, may be a tag, may be a wrist band or head band, may be a removable cover for a device, may be a case or bag that has straps or that has other structures to receive and carry electronic equipment and other items, may be a necklace or arm band, may be a wallet, sleeve, pocket, or other structure into which electronic equipment or other items may be inserted, may be part of a chair, sofa, or other seating (e.g., cushions or other seating structures), may be part of an item of clothing or other wearable item (e.g., a hat, belt, wrist band, headband, sock, glove, shirt, pants, etc.), or may be any other suitable fabric-based item.

Item 10 may include intertwined strands of material that form fabric 12. Fabric 12 may form all or part of a housing wall or other layer in an electronic device, may form internal structures in an electronic device, or may form other fabric-based structures. Item 10 may be soft (e.g., item 10 may have a fabric surface that yields to a light touch), may have a rigid feel (e.g., the surface of item 10 may be formed from a stiff fabric), may be coarse, may be smooth, may have ribs or other patterned textures, and/or may be formed as part of a device that has portions formed from non-fabric structures of plastic, metal, glass, crystalline materials, ceramics, or other materials.

The strands of material in fabric 12 may be fibers, may be yarns or other strands that have been formed by intertwining multiple filaments (multiple monofilaments) of material together, or may be other types of strands (e.g., tubing that carries fluids such as gases or liquids). The strands may include extruded strands such as extruded monofilaments and yarn formed from multiple extruded monofilaments. Monofilaments for fabric 12 may include polymer monofilaments and/or other insulating monofilaments and/or may include bare wires and/or insulated wires. Monofilaments formed from polymer cores with metal coatings (or coatings formed from other materials) and monofilaments formed from three or more layers (cores, intermediate layers, and one or more outer layers each of which may be insulating and/or conductive) may also be used.

Yarns in fabric 12 may be formed from polymer, metal, glass, graphite, ceramic, natural materials as cotton or bamboo, or other organic and/or inorganic materials and combinations of these materials. Conductive coatings such as metal coatings may be formed on non-conductive material. For example, plastic yarns and monofilaments in fabric 12 may be coated with metal to make them conductive. Reflective coatings such as metal coatings may be applied to make yarns and monofilaments reflective. Yarns may be formed from a bundle of bare metal wires or metal wire intertwined with insulating monofilaments (as examples).

Strands of material may be intertwined to form fabric 12 using intertwining equipment such as weaving equipment, knitting equipment, or braiding equipment. Intertwined strands may, for example, form woven fabric, knit fabric, braided fabric, etc. Conductive strands and insulating strands may be woven, knit, braided, or otherwise intertwined to form contact pads that can be electrically coupled to conductive structures in item 10 such as the contact pads of an electrical component. The contacts of an electrical component may also be directly coupled to an exposed metal segment along the length of a conductive yarn or monofilament.

Conductive and insulating strands may also be woven, knit, or otherwise intertwined to form conductive paths. The conductive paths may be used in forming signal paths (e.g., signal buses, power lines, etc.), may be used in forming part of a capacitive touch sensor electrode, a resistive touch sensor electrode, or other input-output device, or may be used in forming other patterned conductive structures. Conductive structures in fabric 12 may be used in carrying power signals, digital signals, analog signals, sensor signals, control signals, data, input signals, output signals, or other suitable electrical signals.

Item 10 may include additional mechanical structures 14 such as polymer binder to hold strands in fabric 12 together, support structures such as frame members, housing structures (e.g., an electronic device housing), and other mechanical structures.

Circuitry 16 may be included in item 10. Circuitry 16 may include electrical components that are coupled to fabric 12, electrical components that are housed within an enclosure formed by fabric 12, electrical components that are attached to fabric 12 using welds, solder joints, adhesive bonds (e.g., conductive adhesive bonds such as anisotropic conductive adhesive bonds or other conductive adhesive bonds), crimped connections, or other electrical and/or mechanical bonds. Circuitry 16 may include metal structures for carrying current, electrical components such as integrated circuits, light-emitting diodes, sensors, controller circuitry for applying currents and/or magnetic fields to materials, electrically controlled devices for illuminating tubing and/or applying control signals to tubing or other strands, and other electrical devices. Control circuitry in circuitry 16 may be used to control the operation of item 10 by controlling electrically controllable (electrically adjustable) components in circuitry 16 and may be used to support communications with item 18 and/or other devices.

Item 10 may interact with electronic equipment or other additional items 18. Items 18 may be attached to item 10 or item 10 and item 18 may be separate items that are configured to operate with each other (e.g., when one item is a case and the other is a device that fits within the case, etc.). Circuitry 16 may include antennas and other structures for supporting wireless communications with item 18. Item 18 may also interact with item 10 using a wired communications link or other connection that allows information to be exchanged.

In some situations, item 18 may be an electronic device such as a cellular telephone, computer, or other portable electronic device and item 10 may form a cover, case, bag, or other structure that receives the electronic device in a pocket, an interior cavity, or other portion of item 10. In other situations, item 18 may be a wrist-watch device or other electronic device and item 10 may be a strap or other fabric-based item that is attached to item 18 (e.g., item 10 and item 18 may together form a fabric-based item such as a wristwatch with a strap). In still other situations, item 10 may be an electronic device (e.g., a wearable device such as a wrist device, clothing, etc.), fabric 12 may be used in forming the electronic device, and additional items 18 may include accessories or other devices that interact with item 10. Signal paths formed from conductive yarns and monofilaments (e.g., insulated and bare wires) may be used to route signals in item 10 and/or item(s) 18.

The fabric that makes up item 10 may be formed from strands that are intertwined using any suitable intertwining equipment. With one suitable arrangement, which may sometimes be described herein as an example, fabric 12 may be woven fabric formed using a weaving machine. In this type of illustrative configuration, fabric may have a plain weave, a basket weave, a satin weave, a twill weave, or variations of these weaves, may be a three-dimensional woven fabric, or may be other suitable fabric. With other suitable arrangements, fabric 12 is knit or braided.

A cross-sectional side view of illustrative woven fabric 12 is shown in FIG. 2 . As shown in FIG. 2 , fabric 12 may include strands 20 such as warp strands 20A and weft strands 20B. In the illustrative configuration of FIG. 2 , fabric 12 has a single layer of woven strands 20. Multi-layer fabric constructions may be used for fabric 12 if desired.

As shown in FIG. 3 , fabric 12 may be a knit fabric. In the illustrative configuration of FIG. 3 , fabric 12 has a single layer of knit strands 20 that form horizontally extending rows of interlocking loops (courses 22) and vertically extending wales 24. Other types of knit fabric may be used in item 10, if desired.

Fabric-based item 10 may include non-fabric materials (e.g., structures such as structures 14 that are formed from plastic, metal, glass, ceramic, crystalline materials such as sapphire, etc.). These materials may be formed using molding operations, extrusion, machining, laser processing, and other fabrication techniques. In some configurations, some or all of fabric-based item 10 may include one or more layers of material. The layers in item 10 may include layers of polymer, metal, glass, fabric, adhesive, crystalline materials, ceramic, substrates on which components have been mounted, patterned layers of material, layers of material containing patterned metal traces, thin-film devices such as transistors, and/or other layers.

FIG. 4 is a diagram of illustrative equipment that may be used in forming fabric-based item 10. Intertwining equipment such as tool 40 may include equipment such as braiding equipment, knitting equipment, and weaving equipment. Tool 40 may be used in forming fabric 12, strands in fabric 12, or other suitable intertwined strands. The strands formed by tool 40 may include strands with various properties. For example, strands 20 may include strands having a core, such as an interior yarn, and an exterior layer, such as an exterior yarn that surrounds the core. The core and exterior layer may have different properties, such as different colors, reflectivities, conductivities, magnetic properties, etc. If desired, tool 40 may include sensors such as sensors 30. Sensors 30 may monitor strands 20 during intertwining (e.g., when dispensing strands 20 into a weaving machine, into a knitting machining, into a braiding machine, etc.). For example, sensors 30 may monitor the optical properties of strands 20, may monitor the diameter of strands 20, may monitor for the presence of magnetic or conductive particles in strands 20, and/or may otherwise monitor strands 20 along their lengths as strands 20 are being incorporated into fabric 12. If desired, markers may be added to the strands during strand formation to assist sensors 30 in monitoring strands 20 during fabric formation. In this way, feedback adjustments may be made to tool 30 to ensure that desired portions of strands 20 are incorporated into desired locations in fabric 12.

Cutting equipment such as trimming tool 34 (e.g., a mechanical cutting tool, a laser cutting tool, or other equipment for cutting yarn) may be used in cutting fabric 12. For example, tool 34 may be used in cutting away undesired portions of fabric 12 and/or portions of strands in fabric 12.

Heating tool 32 may be used in applying heat to tubing and other strands of material in fabric 12. Heating tool 32 may include a laser for supplying heat, a reflow oven, an inductive heating tool for heating solder, a heat gun, a lamp, hot bar equipment, a soldering iron tip, equipment for forming heat by applying current (ohmic heating current) to a conductive strand, or may include other heating equipment.

Additional equipment such as equipment 36 may be used to help form fabric 12, strands for fabric 12, circuitry that is coupled to conductive structures in fabric 12, electrical components, housing structures, and other structures for forming item 10. Equipment 36 may, for example, include equipment for cutting fabric, equipment for laminating fabric to layers of plastic, metal, and/or other materials, equipment for mounting integrated circuits, light-emitting diodes, sensors, buttons, and other electrical circuitry to fabric 12 and/or other portions of item 10, machining equipment for machining parts of item 10, robotic assembly equipment, and/or other equipment for forming item 10.

Etching tool 31 may be used to etch portions of strands 20, either before or after they are formed into fabric-based item 10. Because strands 20 may have a core and an exterior layer with different properties, etching tool 31 may be used to remove portions of the exterior layer to expose portions of the core. Etching tool 31 may include laser etching equipment, chemical etching equipment, heat etching equipment, or any other desired etching equipment. By exposing portions of the core, individual strands 20 may have different properties along their lengths, and fabric-based item 10 may have different properties in different regions, if desired.

The equipment of FIG. 4 may be used to form fabric 12, to process fabric 12, to integrate circuitry 16, fabric 12, and/or additional structures 14 into item 10, and/or to perform other fabrication and processing operations on item 10.

Strands 20 may include strands of material that have cores and exterior layers with different properties. For example, the cores and exterior layers may be different colors, have different conductivities (e.g., the core may be conductive and the exterior layer may be insulating), different reflectivities, different magnetic properties, and/or other different properties. Strands 20 may have portions of the exterior layers that are etched away to expose the cores. In this way, strands 20 may have properties that vary along their lengths. For example, portions of each strand 20 may have different colors, conductivities, magnetic properties, reflectivities, or other properties. An illustrative strand with layers having different properties is shown in FIG. 5 .

As shown in FIG. 5 , a strand, such as strand 20 may have core 44 (also referred to as an inner layer, a core layer, or an interior layer herein) surrounded by exterior layer 46 (also referred to as an outer layer or an external layer herein). In some examples, core 44 may be an interior yarn and exterior layer 46 may be an exterior yarn. Exterior layer 46 may be formed over core 44 in any desired manner. In some examples, exterior layer 46 may be twisted or braided over core 44, or may be co-extruded with core 44.

Core 44 and exterior layer 46 may have different properties. For example, core 44 may have a first color, while exterior layer 46 may have a different color. Additionally or alternatively, core 44 may be conductive and/or magnetic, while exterior layer 46 is insulating. As another example, core 44 may be reflective (e.g., be formed with embedded glass beads that reflect visible light), while exterior layer 46 is not reflective. However, these properties are merely illustrative. In general, core 44 and exterior layer 46 may have any desired properties.

In some cases, it may be desirable to remove portions of exterior layer 46 to expose underlying portions of core 44. An example of removing a portion of exterior layer 46 is shown in FIGS. 6A and 6B.

As shown in FIG. 6A, a strand in fabric item 10, such as strand 20, may have an exterior portion that is removed. For example, exterior layer 46 may be removed in region 48. As shown in FIG. 6A, strand 20 may have thickness T₁ in the region in which exterior layer 46 remains, and thickness T₂, which is less than thickness T₁, in region 48. The removal of exterior layer 46 in region 48 may be performed using any desired process. For example, etching tool 31 of FIG. 4 may be used to remove the portion of exterior layer 46 through laser etching, chemical etching, heat etching, or any other desired process. Although etching tool 31 is described as providing an etching function, any desired tool may be used to remove desired portions of exterior layer 46 and expose underlying portions of core 44.

The removal of exterior layer 46 within region 48 may expose a portion of core 44. In the illustrative embodiment of FIG. 6B, a portion of core 44 is visible/exposed within region 48. The portion of core 44 may have a different functionality from the surrounding exterior layer 46, if desired. For example, the portion of core 44 within region 48 may have a different color or other appearance (e.g., reflectivity) than the color or appearance of surrounding exterior layer 46. Alternatively or additionally, the portion of core 44 within region 48 may be more conductive or more magnetic than exterior layer 46, may be more adhesive than exterior layer 46, or have any other desired property. In some examples, core 44 may be formed from a conductive strand, while exterior layer 46 is insulating. However, this is merely illustrative. In general, core 44 and exterior layer 46 may have any desired properties.

If desired, the different properties of core 44 may allow for the exposed regions of core 44 to have different functionality from exterior layer 46. For example, the exposed regions of core 44 may form a logo, text, a design, a pattern, one or more images, or any other desired markings on exterior layer 46.

As another example, the exposed regions of core 44 may be conductive and may allow for the connection of external equipment, other conductive strands within device 10, or any other desired conductive components to core 44. If desired, fabric 10 may be a smart fabric (e.g., fabric 10 may have conductive strands connected together to form sensors to make measurements, circuitry to process and/or communicate the measurements to external equipment, displays, etc.).

In the embodiment where core 44 is more magnetic than exterior layer 46 or is formed from an adhesive (and exterior layer 46 is free from adhesive), other strands of fabric 10 or external components may be attached to the exposed portion of core 44. For example, components may be attracted to core 44 if it is magnetic. In some cases, core 44 may be both magnetic and conductive (e.g., to allow for wireless charging). In general, however, core 44 may have any desired properties, which may allow for any desired functionality.

Although exterior layer 46 has been described as being etched or otherwise removed to reveal portions of core 44, this is merely illustrative. Alternatively or additionally, some or all of exterior layer 46 may be designed to wear out naturally over time and reveal portions of core 44. For example, exterior layer 46 may wear down gradually to reveal a different color or other appearance of core 44. In this way, the degradation of exterior layer 46 may form a patina with a different color or other appearance.

Although strands in fabric 10 have been described as having a core and an exterior layer, this is merely illustrative. In general, strands in fabric 10 may have any desired number of layers, such as two or more, three or more, five or fewer, or six or more layers. An illustrative example of a strand with more than two layers is shown in FIG. 7 .

As shown in FIG. 7 , a strand in device 10, such as strand 52, may have core 44 surrounded by two layers—exterior layer 46 and additional layer 50. Core 44 and exterior layer 46 may have any desired properties, as previously discussed. Additional layer 50 may also have any desired property, which may be different from a property of exterior layer 46 and/or core 44. This property may include color, conductivity, adhesiveness, a magnetic property, or any other desired property.

A strand having more than two layers, such as strand 52 of FIG. 7 , may be processed similarly to the strand in FIGS. 6A and 6B. In particular, portions of external layer 46 may be removed to selectively expose portions of additional layer 50. In turn, portions of additional layer 50 (and, by extension, external layer 46) may be removed to expose portions of core 44. In some examples, additional layer 50 may have a different color from external layer 46, and regions in which additional layer 50 are exposed may form a logo, text, graphics, designs, patterns, images, etc. Core 44 may be a conductive, magnetic, or adhesive strand that may couple strand 52 to external equipment and provide desired functionality to strand 20 and fabric 10. However, this is merely illustrative. Any desired layer within strand 52 may have any desired functionality, and strand 52 may be etched to expose any desired portion(s) of the internal layer(s).

As discussed, individual strands (such as strands 20 and/or strands 52) may be etched to selectively expose internal layers of the strands, which may have different properties than the external layers in the strands. In some embodiments, it may be desirable to etch individual strands within a fabric to have adjacent strands with matching properties. In other words, the fabric itself may then exhibit the desired property. An example of this is shown in FIG. 8 .

As shown in FIG. 8 , a fabric, such as fabric 12, may have region 52 surrounding region 54. Region 52 may include strands (such as strands 20 and/or 52) that have not been etched (i.e., strands that have the exterior layer still exposed). Region 54, on the other hand, may include strands that have been etched to expose an inner layer within the strand (i.e., strands that have a core or additional interior layer exposed). Because the strands in region 54 are adjacent to one another, the properties of the exposed inner layers of the strands may be present across an entirety of region 54. For example, region 54 may be a different color than region 52, and may therefore form a logo, text, a graphic, an image, a design, a pattern, an image, or other marking. Additionally or alternatively, region 54 may be conductive, allowing for electrical connections of other conductive strands in fabric 12 or other external equipment, or may be magnetic or adhesive, allowing for connections of external fabric or other items. By modifying adjacent strands within fabric 12, region 54 may have a different property from region 52.

Fabric 12 may be used to form any desired fabric-based item. For example, clothing, electronic device covers or cases, or any other desired fabric-based items may be formed using fabric 12.

In some examples, fabric 12 may form a tag on other layers of fabric. Strands, such as strands 20 or 52, in fabric 12 may be selectively etched to form text, logos, designs, patterns, images, or other marking or information on the tag.

As another example, fabric 12 may be used to form a braided cable or a cover for an electronic device cord. Strands, such as strands 20 or 52, in fabric 12 may be selectively etched to form text, logos, designs, patterns, images, or other marking or information on the braided cable or cord cover. Additionally or alternatively, inner layers in the strands may be conductive or magnetic. Etching the outer layers of the strands to selectively expose the conductive or magnetic inner layers may allow for the cable or cord cover to attach to external equipment. However, these examples are merely illustrative. In general, fabric 12 may be incorporated into any fabric-based item.

If desired, custom clothes and other fabric-based items may be formed from strands 20. For example, a user may wish to incorporate text, one or more logos, a design, a pattern, one or more images, or other marking onto a fabric-based item. Based on the user's selections, strands 20 may be selectively etched to reveal an inner layer of the strands and form the text, logos, designs, patterns, images, or other markings. For example, laser etching may be used.

The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination. 

What is claimed is:
 1. A fabric-based item comprising: a layer of fabric comprising strands of material, wherein each of the strands includes an interior yarn and an exterior yarn that surrounds the interior yarn, wherein the layer of fabric has first portions and second portions, wherein the extruded strands in the first portions have some of the exterior yarn removed to expose the interior yarn, and wherein the extruded strands in the second portions have the exterior yarn fully surrounding the interior yarn.
 2. The fabric-based item defined in claim 1, wherein the interior yarn is a first color and the exterior yarn is a second color that is different from the first color, and wherein the layer of fabric exhibits the first color in the first portions and exhibits the second color in the second portions.
 3. The fabric-based item defined in claim 2, wherein the first portions of the fabric layer form a logo.
 4. The fabric-based item defined in claim 2, wherein the first portions of the fabric layer form text.
 5. The fabric-based item defined in claim 1, wherein the interior yarn is conductive and the exterior yarn is insulating.
 6. The fabric-based item defined in claim 5, wherein the second portions of the fabric layer surround the first portions to form openings, and wherein external equipment is configured to attach to the conductive interior yarn through the openings.
 7. The fabric-based item defined in claim 5, further comprising: additional conductive yarn, wherein the second portions of the fabric layer surround the first portion to form openings, and wherein the additional conductive yarn is attached to the interior conductive yarn through the openings.
 8. The fabric-based item defined in claim 1, wherein the interior yarn is magnetic and the exterior yarn is insulating.
 9. The fabric-based item defined in claim 1, wherein the interior yarn comprises adhesive and the exterior yarn is free from adhesive.
 10. The fabric-based item defined in claim 9, wherein the second portions of the fabric layer surround the first portions to form openings, and wherein external equipment is configured to attach to the adhesive interior yarn through the openings.
 11. The fabric-based item defined in claim 1, wherein the interior yarn comprises thermoplastic polyurethane.
 12. The fabric-based item defined in claim 1, wherein the interior yarn comprises a first material with a first reflectivity and the exterior yarn comprises a second material with a second reflectivity that is different from the first reflectivity.
 13. The fabric-based item defined in claim 12, wherein the interior yarn comprises embedded glass beads, and the first reflectivity is greater than the second reflectivity.
 14. The fabric-based item defined in claim 1, further comprising: an additional layer of fabric, wherein the layer of fabric forms a tag that is attached to the additional layer of fabric.
 15. The fabric-based item defined in claim 1, wherein each of the extruded strands further comprise an additional yarn interposed between the interior yarn and the exterior yarn, and wherein the interior yarn, the exterior yarn, and the additional yarn are different colors.
 16. The fabric-based item defined in claim 1, wherein the exterior yarn is configured to wear down gradually over time to expose additional portions of the interior yarn.
 17. A fabric, comprising: a layer of intertwined strands of material having first and second areas, wherein each of the strands of material comprises a core layer surrounded by an exterior layer, and wherein some of the exterior layer is removed to expose portions of the core layer.
 18. The fabric defined in claim 17, wherein the core layer is an interior yarn and the exterior layer is an exterior yarn, and wherein the core layer has a first color and the exterior layer has a second color that is different from the first color.
 19. The fabric defined in claim 18, wherein the exposed portions of the core layer are configured to form a marking selected from the group consisting of: text, a logo, a design, a pattern, and an image.
 20. Apparatus, comprising: fabric comprising strands of material, wherein each of the strands includes a core and an exterior layer that surrounds the core, wherein the core has a first property and the exterior layer has a second property that is different from the first property, and wherein portions of the exterior layer are removed to expose portions of the core having the first property.
 21. The apparatus defined in claim 20, wherein the first property and the second property comprise a characteristic selected from the group consisting of: color, conductivity, magnetism, and reflectivity. 